Feeler head for tubing caliper



Jan. 7;"1958 J. v. FREUD 2,818,654

FEELER HEAD FOR TUBING CALIPER Filed Dec. 30,v 1955 2 Sheets-Sheet 1 JOHN V. FRE

, BmAg-v' A@ L- y mmm Jan. 7, 1958 J. v. FREDD 2,818,654` FEELER HEAD FOR TUBING. CALIPER- Filed Dec. 50, 1955 2 Sheets-Sheet 2 F/gz IN1/Enron JOHN v. FREDD AT'To NEY Patented dan. 7, QEB

ice l FEELER HEAD FR TUBING CALIPER .lohn V. Fredd, Dallas, Tex., assignor, by mesne assignments, to Otis Engineering Corporation, Dallas, Tex., a corporation of Texas Application December 30, 1955, Serial No. 556,579

7 Claims. (Cl. 33-17 8) This invention relates in general to calipering devices and more particularly to a caliper which is designed to locate pits, depressions and other irregular internal surface configurations in tubing, pipe lines and the like which have an extended length.

The invention has particular utility in oil well tubing which normally extends from the surface of the earth downwardly and frequently may be of a length of several thousand feet. This type of tubing is formed of a plurality of metallic pipe sections which are linked together by collars or similar coupling devices. The means for securing the pipe sections together cause changes in the internal diameter of the tubing by increasing or decreasing the diameter at the joints between the pipe sections forming the tubing. These diameter changes in the tubing are quite abrupt and interfere with the movement of the caliper in the tubing.

Calipering and recording devices of the type shown in the Chaney-Barnes Patent No. 2,518,663, dated August l5, 1950, are provided with a plurality of feelers mounted circumferentially about the caliper housing. These feelers are urged outwardly with considerable force into surfacesensing position. As shown in this patent to Chaney- Barnes, the feelers are pivotally mounted on the housing and extend downwardly and outwardly of their connection. When calipering an extended length of oil Well tubing, the caliper, in non-calipering operation, is normally lowered by the influence of gravity from the ground surface to a desired depth and thereafter, in calipering operation, is raised to the earths surface. As the caliper is lowered into the tubing, the feelers strike the collars or couplings above described, causing considerable wear and possible damage to the feelers. There is the further possibility that such couplings and imperfections may prevent the calipering device from descending to the desired depth in the tubing. Such obstruction to the operation is known as being hung-up. This problem exists in all calipering operations whether the feelers extend downwardly and outwardly or whether they extend outwardly at substantially right angles to the caliper housing.

Also, some oil well tubing becomes 'so badly corroded that deep pits and depressions are formed which, in turn, create like obstructions which must be considered. When the calipering device is passed through corroded tubing in non-calipering operation, a feeler or feelers striking such an area could become stuck, or hung-up, .at that point and prevent passage of the device through the tubing. Such obstructions, formed by corrosion, can create the same interference caused by the joints of the pipe sections as explained above. Thus, the present invention has utility where an internal obstruction of any nature in the tubing might prevent passage of the calipering device in the non-calipering direction by intercepting the movement of the caliper feelers.

In order to overcome this problem, it is the practice in this art to lirst retract all of the feelers inwardly toward the housing and hold them as the device is lowered in the tubing. ln this way the feelers will not engage any irregularity capable of obstructing the operation. The means for retracting the feelers is generally known as a latch-and-release mechanism. In utilizing the latchand-release mechanism, the caliper is lowered to the desired depth with the feelers locked in the retracted position, the latch-and-release mechanism is then actuated and the feelers are released to assume the outwardly extended calipering position. Then the caliper is pulled upwardly in the tubing and the calipering feelers sense the pits, depressions and the like which have been formed in the tubing. When the device is moved through the ltubing in calipering operation, the feelers contact all the surface irregularities including the joints between the pipe sections, and ride over such obstructions without any appreciable damage to the feelers, because of the angular relation of the feelers to the housing and the tubing. While the latch-and-release mechanisms referred to solve the problems created by these irregularities inside the tubing for both calipering and non-calipering movement, such mechanisms are complicated and add considerable cost to the construction and maintenance of the calipering device.

lt is frequently desirable to make several records of a calipering operation in a given section of tubing. The reason for this is that no matter how perfectly a calipering device may operate, it is ditiicult if not impossible to obtain a record of all of the pits, depressions and defects in general inside the tubing in -a single calipering operation, because of the practical limitation of the number of feelers which may be distributed about the periphery of the tool. In the devices of the prior art utilizing the above-mentioned latch-and-release mechanisms, it is a tedious operation to caliper and record a given section of tubing a number of times. lf it is desired to repeatedly caliper a portieri of the tubing, say several hundred feet, which is positioned a distance below the earths surface, it is necessary, after lowering the caliper to the desired depth, to release the feelers to contact the tubing in calipering engagement, then raise the calipering device to the desired height to make a. record of the selected length of tubing, and then it is necessary to lift the device from the tubing to reset the latch mechanism and repeat the operation over the previously calipered length of tubing. The presently described device requires no resetting of any latch-release mechanism, but can be raised and lowered over and over again until the entire chart is used.

The main object of the present invention is to provide a calipering device which may be passed through tubing without having to latch the feelers in a retracted position.

Another object of the invention is to provide a calipering device which may be passed through tubing in the non-calipering direction with the feelers automatically withdrawn to a position less extended than that required for calipering, thus reducing wear on the feelers `and enabling the device to be passed through the tubing, in this direction, without danger of being hung up on internal obstructions or irregularities in the tubing.

Still another object is to automatically reduce the force, during movement in the non-calipering direction, which urges the feelers outwardly when the feelers strike an obstruction which could prevent further passage of the calipering device through the tubing.

A still further object of the invention is to provide a calipering device which is capable of repeatedly performing the calipering operation in a given length of tubing without the necessity of removing the calipering device from the tubing.

lt is another object of the invention to provide a calipering device which, when a collar or pit or like depression is encountered by one or more of the outwardly extending feelers of the device moving in a non-calipering direction, all the feelers will automatically be retracted due to the impact of the feeler or feelers on such an irregularity in the internal tubular surface.

These and other objects will be evident in reading the following description of the device with refeernce to the accompanying drawing, in which:

Figure l is an elevational view of a ing device.

Figure 2 is a sectional elevation of the upper portion of Figure l showing the feeler head in the non-calipering position.

Figure 3 is a sectional elevation of the feeler head in calipering position.

Figure 4 is a cross-section of Figure 3 on line 4 4.

Figure 5 is an enlarged cross-section of Figure 3 on line 5 5.

Figure 6 is an enlarged cross-section of Figure 3 on line 6 6.

Before referring to `the details of construction shown in the drawings which illustrate one form of the invention, the basic invention., stated broadly, comprises a caliper With 1 mlmia moans for cach of thc fcclcrs, which means may be moved longitudinally relative to the main housing. A cumming arrangement, positioned in cooperative relation with this improved mounting means, moves the feelers radially of the housing as the mounting means is moved. longitudinally thereof. This compound movement of the feelers is accomplished without in any way altering their caliper-ing function or restricting the movements of the feelers during the oalipering operation.

To illustrate one form of device with which this improved feeler head can be used to advantage, Figure 1 shows a complete, self-contained tubing caliper as` moditied by this disclosure. This complete mechanism with another form of feeler sub-combination is described and claimed in my Patent No. 2,596,924! issued; May 13, 1952, to which reference is made for oomplete disclosure of that apparatus.

Referring now to Figure l, the top sub A is the connection by means of which the caliper is suspended in the tubing. Sub A is threadedly connected to the body framework of the feeler assembly which is indicated by the letter C following the lettering in the above-noted patent. This feeler head, assembly C represents 011,1. main consideration and will be described in detail. Below this section are housed the remaining elements of the mechanism which record the feeler movement and drive the recording elements. Further reference to` these elements is not necessary to an understanding of the feeler mechanism of this application and will not be made.

Figure 2 is a sectional view of the two sections A and C referred to above. Sub, A is machined to provide an upper threaded portion 10 arranged to engage a wire line or other-tool or connector notv shown. A similar threaded portion` 12 (Fig. 2) on the lower end of Sub A is adapted to connect with the feeler head assembly about which. the feeler elements are grouped. An internal bore 16, in subV A provides room for movement of the feeler elements in response to feeler movement which will be described later.

Comparison with Paten-tf No, 2,596,924 will show subcombinations serving like purposes separated by a latchrelease mechanism lettered B therein, which it is one of the purposes of the instant disclosure to eliminate. The component parts of section C, the feeler head section serving this purpose and now, about to be disclosed, is structurally and operatively different from the device shown in that patent, and will be described here in detail.

Returning to Figure 2, and referring also to Figures 3, 4 and 5 for clarity, the body frame, member 14 of the complete caliperfeeler head assembly fastened to sub A as described above h engages a longitudinally movable member or cage 18 which supports the pivotal points of the individual feelers. A plurality of pcriphcrslly spaced; guide, rods. 2:2 positioning individually operating springs 2,4. arev top positioned by drilled portions 2.6.. (See Fig .`4,) Thesedrilled pob.

body frame 14 of the tions arc pressure connected by vcat holes 13.. The bottoms of these guide rods 22 engage the segments of the feeler contact member 28, as shown in Figure 5, which transmit the pressure of springs 24 to the respectively engaged feelers 30. Compressive force is built into these springs 24 by preloading and is maintained to supply the individual feeler operation by abutting the loaded spring against .llenas ,36 above thc segment of the feeler contact member 28 and against the downwardly facing shoulder 20 o'f the pivotal support member or cage 18 in which the screws 26a are instlld- Holes 1 3 pierce cage 18 admitting external pressure to drilled portions 26. By this means the internal and external pressure is bal-- anced permitting unobstructed operation of the movement elements. Pivotal suspension hoop 32 resting in groove 34 at the bottom of the cage 18 positions the feelers in the cage for all operations.

Centrally positioned within thc fcclcr head. thc conter los plunger and centering spring 42 arc arranged to more longitudinally of. the device and cxcrt uniform pressurc on all thc fcclcrs 30 On thc centering plusser 40 a flange 44 having a downwardly facing shoulder 41 engages upwardly facing shoulders 43 on the inwardly projecting portions 46 of the segmented feeler contact members 28, This shoulder 41 engagement being above the inwardly projecting portions 46 of the separately movable segments of Contact member 2 8 permits the segments to be separately urged downward by peripheral springs 24. It will be noted that the segments have cam surfaces 29 which cooperate with cam surfaces 27 formed on the upper surface of the feelers 30. These cam surfaces extend inwardly of the pivotal suspension hoop 32. Thus, the segments of contact member 2,8, which are independently "urged ydownwardly by their respective preloadfcd springs. v24 acting through guide rods 22,. individually urgeeilih 0f the feelers 30 outwardly. Consequently the feelers 30 are free to` act separately and collectively depending on the irregularity of the caliperedV internal surface ofthe tubing- As is evident from the above description, the functions of the described elements can be summarized briefly, as follows.: The centering plunger 40 constantly exerts equal pressure on all feelers maintaining the caliper in proper alignment within the tubing. Individually each feeler 30 is urged outwardly to engage the tubular wall by the feeler'bearing segments of contact member 28 as urged by rods 2 2, and springs 24. The feelers 30 pivotally suspended in cage 18 by hoopv 32, are free, to engage a motion transmitting element 5,0, supported by spring 52, irl longitudinal movement. Fcclcr motion imparted to element 5 0 proeflts a. moans for recording the feeler operation- In addition to the above and adjacent element 5.0 and hoop pivot 32 a second bearing clement 6,0., as shown in Figures 2,.. 3 and 6, effectively cooperating, with fcclers 3Q, is shown. This bearing element 6,0 takes the form of a bandl or hoop. encircling the feelers and acts to depress or permit extension of the4 feelers depending on the, portion of the cam surface of the `feelers engaging the` bearing band. By longitudinally moving the feelers relative to the body of the caliper, a Selected portion of thisl earn surface can be brought into properV position with the bearing element or hoop. 60. This hoopy is positioned in groove 62. in body frame 1.4.and becomes a permanent part ofl that element.

Examination of the. feelers 30 as illustrated in the figuresv of the. drawing isl invited, in order to distinguish the QQmbinatiOn Shown here from known feeler mechanisms. In elfes/ation, shown in Figures 2 and, 3, the fcclcr 30. is a modified bell-crank clement comprising an inwardly extending arm 31 and an outwardly extending arm balanced to pivot about. hooi; 3.2. The. inwardly extending arm. 3,1 projects. from. pivot 32. to form contact with; motion-transita clcmcaill in thccalincrns Position as shown in Figure 3e A ratio of 1 to` 4 is. illustrated between the inwardly extending arm eective points of suspension and contact, and the distance along the outwardly extending arm between pivot 32 and feeler point 35. It will be recognized that a wide variation in ratio of inwardly and outwardly extending arms of the feelers is possible. The proportion selected will depend upon the function to be performed, the nature of the recording element operated, and the results desired. By means of the selected ratio and proper camming of the contacting surfaces the retraction and extension of feelers 30 is accomplished.

Starting with the portion of feeler 30 in bearing engagement on pivotal hoop 32 as the beginning of this camming surface, the inwardly extending arm 31 is proled to allow complete retraction into the body frame 14 and retain constant engagement with the contacting surface 29 of member 23 in both calipering and noncalipering positions. The cam surface portion 27 of arm 31 between member 28 and motion-transmitting element t) is tapered to prevent binding and also to reduce friction to a minimum. Continuing to follow the profile of feeler 30 in a clockwise direction, the inner edge of outwardly extending arm 33 is directioned relative to arm 31 to allow the feeler to be retracted into frame body 14 until it rests adjacent member 50 and spring 52.

In shaping the bottom of feeler 3), the most practical angular relationship with the inner edge for sliding over obstacles in the non-calipering movement in tubing is assumed. This action is illustrated in Figure 2 by the tube and collar assembly and engaging feeler shown in phantom lines compared with the full lined position of the feeler assumed as a result of striking the tubing T in downward movement. Disclosure of operation, later, will make this movement clear. An angle of 45 degrees (for this bottom surface) is used here. A greater angle would make engagement with collar recesses, or more specifically the upwardly facing ends of lengths of well tubing, for example, too abrupt, and might bind the device. A lesser angle would prevent the feeler from determining the true depth of small but deep pits in the calipering operation.

A proper distance outward from the inner edge to assume calipering engagement in sufficient depth to. detect dangerous pits and fissures, contact 35 is mounted. A ground edge of long wearing metal or a conventional ball of small diameter as previously disclosed in this art, or other sensing means, are equally acceptable.l This sensing means is extended into operating contact by angularly shaping the outer surface of feeler 30 relative thereto.

Continuing the clockwise description of the. feeler edges, the engaging surface immediately above and adjacent to the sensing means 35 is arranged to engage collar recesses or other pits and surface irregularities and depress the feeler without binding. The edge above this sensing element 35 projecting angle is directioned to lie flat with body member 14 in normal retraction and leads into a cam surface 37 designed to engage stationary camming hoop 69 in the calipering and non-calipering positions depending on the longitudinal position of the feeler relative to the camming hoop. The lower of these positions permits the normal calipering position of the feeler (Fig. 3) while the upper position (Fig. 2) retracts feeler 30 by the clect of the camming edge 37 bearing on the hoop 60. Between this camming edge 37 and the pivotal bearing surface engaging bearing hoop 32 is a surface directioned to connect with the retracting surface 37, but profiled to allow feeler 39 to project into calipering con tact with thev tubing inner wall without interference with camming hoop et? when in the calipering, or lower, position (Fig. 3).

To aid in understanding the operation of the feeler head as a subcombination, reference is made to all the figures in the attached drawing, and particularly to Figv ures 2 and 3.- In these two views, the former, showing the feelers in phantom line riding the tubing inner wall, or more fully withdrawn into the non-calipering position as a result of the non-calipering engagement of the feelers forcefully striking surface depressions such as coupling collars, pits and like depressions in the tubing during descent, is in sufcient detail to support a broad description of the general relationship of cooperating elements. The second detailed gure, number 3, shows the position of the feelers and cooperating elements extended into the calipering position in contact with the inner wall of a representative tube T, in calipering operation.

The caliper as shown in Figure 1, and as previously stated, is one form of device with which the feeler mechanism of this invention can be used. A complete caliper in this figure is set forth only as an example, and is not intended to limit the usefulness of this sub-combination in broader applications. Consequently, the description of operation will be limited to the feeler head and will not repeat the details of the calipering instrument already well known from the patent of reference.

The calipering device as shown in Figure 2 with the feelers in the more or less retracted positions is shown in the non-calipering operation preliminary to calipering. To begin the operation the device is inserted into the tubing and the feelers are released. They extend into engagement with the interior wall of the tubing as shown in Figure 3, preliminary to the downward movement of the caliper. As the caliper drops or is rapidly lowered into the tubing to assume the bottom hole position from which the calipering operation is to begin, the upward force on the lower cammed edge of the feelers caused by striking against the tubing collar recesses, or engaging pits or like obstructions, or moving through well uids,

vduring this rapid descent, urges the feelers upward as shown from the phantom line position to the full line position in Figure 2. Normally the preloaded feeler springs 24 will urge the respective feeler arms 30 toward operating contact with the hoop 32 during this upward pressure effect when retracted as well as when fully extended in the lower or calipering position. However, when one or several of the feelers strike an obstruction during this downward passage, the cage assembly 18 as a unit is caused to slide upwardly on the housing against the resistance of the centering spring 42 alone. Although the centering spring 42 is somewhat stronger than an individual feeler spring 24, and a single feeler striking an obstruction might be lifted from the ring 32, the distance the feeler will be lifted will be Very small because the feeler spring 24 will have a high spring rate and the centering spring 42 will have a low spring rate. In other Words, after a feeler spring has been compressed a Very short distance, it will be stronger than the centering spring. As a result the respective feelers and cage with included elements are lifted with respect to the body frame member 14 and urged inwardly by contact with bearing hoop on the outer cammed edges of the feelers. Thus the resulting momentary effect is to urge the feelers into the retracted position shown in Figure 2 during this non* calipering movement enabling them to pass over the contacted obstructions without interruption to reach the calipering starting position. The extent of this automatic retraction of the feelers, it will be realized, is proportionate to the speed of descent and the shape and size of the resistance encountered by the feelers, compressive movement of theV centering spring in response to the vertical movement of the pivotal support member, and the effect ofv the hoop bearing surface 60 on the cam-shaped edges of the feelers.

On reaching the bottom of the drop distance, the centering spring 42 assumes its normal operating position, being no longer compressed by the vertical movement of the cage, and the separate feeler operating springs 24, without change in their pre-loaded force, assume the calipering position assisted by the return of the cage to normal position. The cage 18 moves downwardly by force of centering spring 42 and the feelers released by bearing hoop 60 extend outwardly into tube-wall contact.

Figure 3 shows this position for calipering and will be followed in tracing the calipering operation. The centering spring 42 and the stylus lift spring 52, of which the latter is selected as the weaker element to support the motion transmitting element 50 in constant contact with the feelers during calipering, are shown with the feelers urged outwardly. Points 35 of the feelers contact the tubing walls. As the caliper is raised in the tubing, the feelers seek pits and depressions, separately responding to each and transmitting the depth of the deepest one by the eiect of the greatest radiusv attained depressing the motion transmitting element S a distance proportional to the greatest radius.

As the caliper is moving in an upward direction, the frictional engagement of the feeler sensing tips 35 urges the feelers downward relative to the feeler body frame, further clearing bearing hoop 60 and more rmly seating on pivot 32. Consequently there is no tendency to urge the feeelrs into the retracted position described above, as there is no force directed to move them upwardly in the feeler head body against the operating force of centering spring 42.

It will be evident that this construction and resulting function is particularly advantageous in repeated calipering. The operations in descent and ascent above described can be repeated between chosen depths in a well tubing, for example, as long as the attached recording mechanism can receive the measured information. There is no need to remove the feeler section for re-setting after each caliper run as the feelers are withdrawn and extended at the proper times, automatically.

The invention claimed is:

l. A calipering device for calipering an internal tubing wall comprising a housing, a plurality of independently movable calipering` feelers mounted on said housing, a plurality of individual pressure means each having a predetermined force for urging each of said feelers outwardly for calipering the tubing, means for supporting all of said individual pressure means for longitudinal movement relative to said housing without changing their predetermined force, and means for exerting an additional force for urging all of said feelers outwardly into tubing calipering position.

2. A calipering device for calipering an internal tubing wall comprising a housing, a plurality of independently movable calipering feelers mounted on said housing, a plurality of individual pressure means each having a predetermined force for urging each of said feelers outwardly for calipering the tubing, means for supporting all of said individual pressure means for longitudinal movement relative to ysaid housing without changing their predetermined force, and means for urging said supporting means into contact with said feelers for exerting an additional force common to all'of said feelers for urging all of said feelers outwardly into tubing calipering position.

3. A calipering device for calipering an internal tubing wall comprising a housing, a plurality of calipering feelers, means for pivotally connecting said feelers to said housing, means for longitudinally moving said pivotal connecting means-relative to said housin each of said feelers having a cammed surface, and meansi mounted on 'said housing cooperating with said cammed surfaces to move all of said feelers laterally of said hous- Y 1 A alpi-8,654"

ing when said pivotal connecting means are moved longitudinally of said housing.

4. A caliperingV device for calipering an internal tubing wall comprising a housing, a cage slidably supported on said housing, la plurality of independently movable calipering feelers mounted on said cage, a plurality of individual pressure means mounted on said cage for independently urging each of said feelers outwardly of said housing for calipering the tubing, and means for exerting an additional force for urging all of said feelers outwardly into tubing calipering position.

5. A calipering device for calipering an internal tubing wall comprising a housing, a cage slidably supported on said housing, a plurality of independently movable calipering feelers mounted on said cage, and a plurality of individual pressure means mounted on said cage for independently urging each of said feelers laterally of said housing for calipering the tubing, each 0f said feelers having a cammed surface, and a member extending peripherally of said housing for cooperating with said cammed surfaces, whereby when one of said feelers engages .an obstruction when the device is moved through the tubing in one direction, said feeler will move said cage longitudinally of said housing to simultaneously move all of said lfeelers longitudinally of said housing and said member will move all of said feelers laterally inwardly toward said housing.

6. A calipering device for calipering an internal tubing wall comprising a housing, a cage supported on said housing for longitudinal movement, a plurality of independently movable calipering feelers positioned on said cage and longitudinally movable therewith, pressure means mounted on said housing common to all of said feelers for urging all of said feelers laterally outwardly rela-l tive to said housing, a plurality of individual pressure means eac-h having a predetermined force mounted in said cage for independently urging each of said feelers laterally outwardly of said housing, each of said feelers having a cammed surface facing outwardly from the housing, and a member extending peripherally of said housing for cooperating with said cammed surfaces, whereby when one of said feelers engages an obstruction when the device is moved through the tubing in one direction, said feeler moves said cage' longitudinally of said housing thus simultaneously moving all of said feelers longitudinally of said housing against said common pressure means, said individual pressure means moving longitudinally of the housing with said cage without changing their predetermined force, and said member engaging and moving said feelers laterally inwardly of said housing.

7. A feeler head for internal tube Wall calipering devices comprising a body member, a 4cage slidably supported on said body member, a plurality of feelers pivotally mounted on said cage, resiliently urged guide rods peripherally positioned in said cage to oper-ate each of said feelers respectively, a segmented motion-transmitting member between the feelers and the guide rods, a resiliently responsive centering plunger in operating engagement with .all of said segments, and a xed bearing element positioned below the pivotal mounting and in contact with said feelers, whereby upward force on the feelers causes them to withdraw from calipering contact with the tubing wall.

References Cited in the le of this patent UNITED STATES PATENTS 2,640,271 Boucher June 2, 1953 2,719,361 Montgomery et al. Oct. 4, 1955 

